package com.example.forum.Interceptor;

import com.example.forum.config.AppConfig;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;


//登录拦截器
@Component
public class LoginInterceptor implements HandlerInterceptor {
    @Value("${forum.login.url}")
    private String defaultURL;

    //前置处理（对请求的预处理），true继续流程，false流程中断
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //获取session对象
        HttpSession session=request.getSession(false);
        //判断session是否有效
        if(session!=null&&session.getAttribute(AppConfig.USER_SESSION)!=null){
            //用户已登录，校验通过
            return true;
        }
        //校验url是否正确
        if(!defaultURL.startsWith("/")){
            defaultURL="/"+defaultURL;
        }
        //校验不通过，跳转到登录界面
        response.sendRedirect(defaultURL);
        return false;
    }
}
